Electrode for arc-lamps.



W. T. CONN.

ELECTRODE FOR ARC LAMPS.

APPLICATION IEILED 1.23.1, 1909.

1,002,645, Patented Sept. 5, 1911.

WITNESSES; INVENTEIFQ fiwwlm UNITED srA'rns PATENT OFFICE.

WALLACE T.

- or ctnvn'mnn, 01110, a coarom'rron or NEW mess CONN, OI LAKEW OOD, OHIO, A SSIGNOR T0 NA'IICNAL CARBON COMPANY,

ELECTRODE FOR ARC-LAMPS.

Specification of Letters Patent.

Patented Sept. 5, 1911.

Application filed April 1, 1909. Serial'No. 487,302.

State of Ohio, have invented a certain new and useful Improvement in Electrodes for Arc-Lamps, of which the followmg is a full, clear, and exact description.

This invention relates to improvements in the construction .of electrodes adapted especially for use as negative electrodes in the so-called vertical flaming arc lamps ,-.that is to say, flaming arc lamps in which the negative electrode is placed directly over and in alinement with the positive electrode. lln lampsof this character, using these electrodes'as they have heretofore been made, the light is unsteady and the consumpt on of the negative electrodes is unduly rapid because the arc does not remain steadlly between. the ends of the positive and negative electrodes, but, on the contrary, shifts about, sometimes springing from the end of the negative electrode and sometimes from the sides thereof at various and sometimes considerable distances from the end thereof.

The object of the present invention is to steady the light and prevent the waste of the ne ative electrodes, by providing a negative e ectrode adapted especially for the stated. use, and so constructed that the arc will always spring from the end instead of sometimes from the side thereof.

The invention consists of an electrode having securedaround it a covering of insulating material; and also in the construction, substantially as described, whereby this insulating coating may be made very thin so as to'minimize the production of slag and ash within the lamp,all of which will be hereinafter'described andpointed out definitely'in the claim.

In the drawing, Figure 1 is a sideview partly broken away in section of-an electrode embodying the invention. Fig. '2 is a transverse sectional view of the same.

Referring to the parts by letters, A rep-' resents the electrode proper, or conductor; and this part of the structure may be of any ordinary or suitable construction. Usually they consist of ashell of carbon a, and a core a made of carbon dust and water glass. Sometimes these electrodes are made ofhomogeneous mixture of carbon dust and -.water glass. Sometimes a color imparting salt is incorporated into the mixture of carbon and water glass. The specific construction of the conductor or electrode 4 proper is, however, immaterial to the present invention, and, as stated, this part may be of any ordinary or suitable construction. Applied externally to this conductor is a coating of insulating materialthat is to say, material which is an insulator to the. current when the electrode,

is in use and therefore subject to the heat ineident to such use. This material 'may be fire clay or asbestos or some mixture of these, or. any other suitable material. It is, ofcourse, desirable that the quantity of this insulating material used shall be reduced to the minimum, because when an electrode coated with such material is used the material will be disintegrated and a slag or ash or both will be produced, which may drop into the lamp.- In order that the quantity of insulating material may be so 'minimized a shell C of carbon is secured tightly, preferably molded over the thin coating of insulating material. When this external supporting shell G is employed it is not necessary that the insulating coating B shall be unbroken. It may be, but itmay also be made of any desired form which will produce air cells b in which air will be imprisoned; and in that event the thin layer of air in these cells may serve as a part of the insulating covering of the electrode A. As shown in the drawing, the insulated coating of the electrode proper does not extend to the upper end thereof. A short sectional of the upper end of the electrode A is left grasped by the clasp provided in the lamp for this purpose.

1 The shell 0 may be of any thickness required to properly support the insulating covering B, and to so withstand the heat of use that its consumption will practically be equal in rate to the consumption of the conductor or electrode A, and so also that its presence will prevent the fusion and disintegration of the insulating coating back from the end of the electrode. The carbon coating when it is consumed produces very little ash or slag and therefore is not objectionable from that view point.

uncovered so that it may conveniently be In using the described electrode it will be found that the arc will always s' ring from the end of the electrode A, an not from the side thereof. This will, of course, steady the light and will prevent that wasteful consumption 'of the negative electrode which is common in lamps ofthis character where the negative electrodes are not coated with insulated material and wherein, therefore, the arc shifts about from the end to the side of said electrode.

While the described electrode will find its greatest field of usefulness as a negative electrode inthe vertical flaming arc lamps, there may be other uses inwhich it will be valuable.

Having (described my invention, I claim:

A negativeelectrode for flaming arc lamps having a main electrode portion, and means for maintaining the are at the end of the electrode comprisin a coating of insulating 20 material about sai main port-ion, and a shell of carbon surrounding the insulating coating.

In testimony whereof, I hereunto afiix my slgnature in the presence of two witnesses. 25

WALLACE T. CONN.

Witnesses:

GEO. M. SMITH, C. W. SANFORD. 

